The present invention relates to a television phone adapter that connects a telephone, a video input device, and a video output device to realize a television phone.
As digital networks, networks utilizing IP (Internet Protocol) are coming to the front. In particular, there appear broadband lines such as ADSL (Asymmetrical Digital Subscriber Line) and FTTH (Fiber To The Home) through which high-speed data communication is made possible, and now an IP network can use such a broadband line. An IP network uses a method called “best effort” that does not assure transfer of all data. In a best effort method, users share a band of a network. Accordingly, a cost for using the equipment is low, and a broadband line can be used at a low charge. Recently, taking such advantages, television phones utilizing an IP network is proposed.
“A Debut of a simple IP television phone! Television phone Adapter” (tentative title) [online], retrieved on Apr. 9, 2003, Internet <http://www.suncomm.co.jp/vpa/index.html> (hereinafter, referred to as “Non-Patent Document 1”), “Sun Communications, An adapter for adding a moving picture function to an IP telephone” [online], retrieved on Apr. 9, 2003, Internet <http://bb.watch.impress.co.jp/cda/event/4162.html> (hereinafter, referred to as “Non-Patent Document 2”) and Sun Communications, Catalog, “Catalog—Television phone Adapter (tentative name)”, April 2004 (hereinafter, referred to as “Non-patent Document 3”) disclose a television phone adapter for using an ordinary analog telephone to realize a television phone. This television phone adapter is equipped with a liquid crystal display unit and a camera and connected with an analog telephone and an ADSL modem having an IP telephone adapter function. A simple button operation on the television phone adapter can switch from an IP telephone without video function to an IP telephone with video function (i.e., television phone) and vice versa. This television phone adapter realizes a television phone as follows. Namely, first, using the ADSL modem having the IP telephone adapter function, the television phone adapter establishes a connection for voice communication. Next, using this connection for voice communication, the television phone adapter exchanges IP addresses used for video communication with a communication partner. Then, using the exchanged IP addresses, the television phone adapter establishes a connection for video communication.
Further, Japanese Patent Laid-open No. 2000-312262 (hereinafter, referred to as “Patent Document 1”) discloses a technique of using a key telephone as an input device for a computer. Here, a key telephone means a telephone having various functions for extension. A key telephone has various function keys in addition to fundamental dial keys 0-9, * and #. According to Patent Document 1, a key information extraction unit is arranged between a key telephone and a key telephone main unit. When key information is sent from the key telephone in an on-hook state, the key information extraction unit detects the key information and sends the key information to the computer. Using a translation table, the computer translates the key information received from the key information extraction unit into control information.